Internal Strains in Healthy and Degenerated Lumbar Intervertebral Discs

Tsantrizos, Anthony; Ito, Keita; Aebi, Max; Steffen, Thomas

doi:10.1097/01.brs.0000181052.56604.30

Cited by 82 publications

(60 citation statements)

References 31 publications

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“…Nuclear migration during bending subjects the anulus to tensile radial strains of up to 10%, depending on disc condition, region and bending modality [66]. Anulus deformation in response to such strains occurs by way of both transverse collagen bundle elongation and separation at lamellar interfaces [52].…”

Section: Functionmentioning

confidence: 99%

The elastic fibre network of the human lumbar anulus fibrosus: architecture, mechanical function and potential role in the progression of intervertebral disc degeneration

Smith

Fazzalari

2009

Eur Spine J

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Elastic fibres are critical constituents of dynamic biological structures that functionally require elasticity and resilience. The network of elastic fibres in the anulus fibrosus of the intervertebral disc is extensive, however until recently, the majority of histological, biochemical and biomechanical studies have focussed on the roles of other extracellular matrix constituents such as collagens and proteoglycans. The resulting lack of detailed descriptions of elastic fibre network architecture and mechanical function has limited understanding of the potentially important contribution made by elastic fibres to healthy disc function and their possible roles in the progression of disc degeneration. In addition, it has made it difficult to postulate what the consequences of elastic fibre related disorders would be for intervertebral disc behaviour, and to develop treatments accordingly. In this paper, we review recent and historical studies which have examined both the structure and the function of the human lumbar anulus fibrosus elastic fibre network, provide a synergistic discussion in an attempt to clarify its potentially critical contribution both to normal intervertebral disc behaviour and the processes relating to its degeneration, and recommend critical areas for future research.

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Section: Functionmentioning

confidence: 99%

The elastic fibre network of the human lumbar anulus fibrosus: architecture, mechanical function and potential role in the progression of intervertebral disc degeneration

Smith

Fazzalari

2009

Eur Spine J

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“…Several in vivo studies of healthy individuals, employing magnetic resonance imaging (MRI), have reported IVD deformation in the sagittal and axial plane [13][14][15][16] and in scoliosis [17]. Limited data on NP deformation in lateral flexion exist mainly from cadaver studies [18]; however, no investigations to date have reported in vivo NP deformation in response to induced lateral flexion.…”

Section: Introductionmentioning

confidence: 99%

Nucleus pulposus deformation in response to lumbar spine lateral flexion: an in vivo MRI investigation

Fazey

Takasaki²,

Singer

2010

Eur Spine J

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Whilst there are numerous studies examining aspects of sagittal plane motion in the lumbar spine, few consider coronal plane range of motion and there are no in vivo reports of nucleus pulposus (NP) displacement in lateral flexion. This study quantified in vivo NP deformation in response to side flexion in healthy volunteers. Concomitant lateral flexion and axial rotation range were also examined to evaluate the direction and extent of NP deformation. Axial T2-and coronal T1-weighted magnetic resonance images (MRI) were obtained from 21 subjects (mean age, 24.8 years) from L1 to S1 in the neutral and left laterally flexed position. Images were evaluated for intersegmental ranges of lateral flexion and axial rotation. A novel methodology derived linear pixel samples across the width of the disc from T2 images, from which the magnitude and direction of displacement of the NP was determined. This profiling technique represented the relative hydration pattern within the disc. The NP was displaced away from the direction of lateral flexion in 95/105 discs (p \ 0.001). The extent of NP displacement was associated strongly with lateral flexion at L2-3 (p \ 0.01). The greatest range of lateral flexion occurred at L2-3, L3-4 and L4-5. Small intersegmental ranges of axial rotation occurred at all levels, but were not associated with NP displacement. The direction of NP deformation was highly predictable in laterally flexed healthy lumbar spines; however, the magnitude of displacement was not consistent with the degree of intersegmental lateral flexion or rotation.

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“…The physiological loading condition of a NP could then be seen as a semi-confined situation. The NP is extremely deformable and it is not uncommon to observe strain amplitudes as large as 12.5% in physiological loading conditions (Tsantrizos et al, 2005). In parallel to its remarkable deformation property, in vivo experiments on baboon showed that removing the NP decreases the damping properties of the IVD (Quandieu et al, 1983).…”

Section: Introductionmentioning

confidence: 99%